It makes sense in a both-played-by-Patrick-Stewart way, but is otherwise brain-rottingly stupid.****END SPOILER****

Upon mentioning Planet X's malarkey to my brother, he suggested the possibility of doing a similar Kevin Bacon crossover; my first thought is to combine Footloose and Tremors for a dance-tastic drama featuring giant, man-eating worms (perhaps a specific series of dance steps could confuse the worms, allowing safe passage).

What crossovers are you reading / have you read? Were they strokes of brilliance, the source of all inanity, or just "meh"? Are there any crossovers you'd give a leg and arm to see?